It is not known if theme paints the assigned background or not, in which case we should not mark such elements as opaque.
Created attachment 195399 [details] Patch
Comment on attachment 195399 [details] Patch Did this break a real site? If so, please say so in the change log.
I am not aware of any real site being broken. It breaks the example attached in the chromium bug: crbug.com/223490
Comment on attachment 195399 [details] Patch Attachment 195399 [details] did not pass chromium-ews (chromium-xvfb): Output: http://webkit-commit-queue.appspot.com/results/17324207 New failing tests: compositing/contents-opaque/control-layer.html platform/chromium/virtual/softwarecompositing/contents-opaque/control-layer.html
Created attachment 195454 [details] Archive of layout-test-results from gce-cr-linux-02 for chromium-linux-x86_64 The attached test failures were seen while running run-webkit-tests on the chromium-ews. Bot: gce-cr-linux-02 Port: chromium-linux-x86_64 Platform: Linux-3.3.8-gcg-201212281604-x86_64-with-GCEL-10.04-gcel_10.04
Comment on attachment 195399 [details] Patch Attachment 195399 [details] did not pass chromium-ews (chromium-xvfb): Output: http://webkit-commit-queue.appspot.com/results/17286551 New failing tests: compositing/contents-opaque/control-layer.html platform/chromium/virtual/softwarecompositing/contents-opaque/control-layer.html
Created attachment 195461 [details] Archive of layout-test-results from gce-cr-linux-08 for chromium-linux-x86_64 The attached test failures were seen while running run-webkit-tests on the chromium-ews. Bot: gce-cr-linux-08 Port: chromium-linux-x86_64 Platform: Linux-3.3.8-gcg-201212281604-x86_64-with-GCEL-10.04-gcel_10.04
Committed r147127: <http://trac.webkit.org/changeset/147127>